The line comes from Squid Game, the Netflix survival drama centred on Seong Gi-hun, known as Player 456. After winning the deadly competition in the first season, Gi-hun later returns to the games, and his claim that he has played them before became a widely shared clip online. Editors on short-form video platforms reused the five-second moment as a shorthand for experience, foreknowledge and grim confidence, especially in gaming, challenge and reaction videos. Its short length and instantly recognisable context keep it useful long after the show's later seasons.